Triazole additive boosts strob activity

21 April 2000

Triazole additive boosts strob activity

By Louise Impey

AN additive included in formulations of one triazole fungicide could help the activity of a key strobilurin fungicide.

Fluquinconazole-based Foil and Flamenco from Aventis Crop Science both contain the adjuvant Maximiser to boost activity. Now it seems Amistar (azoxystrobin) activity can also benefit when it is included in the tank mix, boosting both disease control and yield potential.

"Maximiser was originally added to fluquinconazole to improve its foliar penetration and so give effective curative activity," says Alison Daniels of Aventis.

"But it has also shown to have an impact on the activity of azoxystrobin, by improving its uptake into both the fungus and the upper leaf layers, giving it some curative properties."

The effect is most pronounced with powdery mildew in wheat. But good activity enhancement is also seen with Septoria and rusts.

"The effect is seen with azoxystrobin because it behaves in a similar way to fluquinconazole, despite being different chemistry. Maximiser does not influence the other strobilurins, kresoxim-methyl and trifloxystrobin, in the same way," says Ms Daniels.

Les Sykes, development manager with agrochemicals distributor Sands Agricultural Services, saw the effect in trials last year. He believes an Amistar/Flamenco tank-mix is a good choice at T2.

"We compared a Flamenco/ Amistar programme with one based on epoxiconazole and kresoxim-methyl. The former gave us a yield of 10.89t/ha and a return on investment of £186/ha, compared with 10.55t/ha and a return of £147/ha."

He advises growers to consider both variety and disease pressure before making their final choice. "With Maximiser, fluquinconazole offers the best mildew activity of any triazole on the market and is as good as the others on Septoria. Its one potential weakness is yellow rust."

A Flamenco/Amistar mix at T2 is a good partnership, especially with the improved performance of the strobilurin, he says. "Our work shows that it should give growers a cost benefit over other options." &#42

Zenecas view

"Triazole partners for Amistar should be selected on the basis of specific disease pressure," says Peter Froggatt, technical manager at Zeneca. "We have tested fluquinconazole with Maximiser in an Amistar programme and found the combination extremely effective for the control of Septoria. However, for other foliar diseases, different triazole partners may be required, and the flexibility of Amistar allows the most suitable one to be included in the tank mix."

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